This application claims priority to Korean Patent Application No. 2003-0058004, filed on Aug. 21, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates generally to disk drives, and more particularly, to a disk drive having a cover plate formed with preload tension across the cover plate for higher stiffness.
2. Description of the Related Art
Hard disk drives (HDDs), as data storage devices for computers, use read/write heads to reproduce data from or record data on a disk. The read/write head performs such read/write functions by being moved by an actuator to a desired position while being lifted over the disk.
FIG. 1 shows an exploded perspective view of a conventional hard disk drive. Referring to FIG. 1, a conventional hard disk drive includes a base member 11. A spindle motor 30 for rotating a disk 20 and an actuator 40 for moving a read/write head over the disk 20 are installed on the base member 11.
The actuator 40 includes a swing arm 42 rotatably coupled to a pivot bearing 41 installed on the base member 11. The actuator 40 also includes a suspension 43 installed at one end portion of the swing arm 42. The suspension 43 supports a slider having the head mounted thereon as the head is moved over a surface of the disk 20. A voice coil motor (VCM) 45 is controlled by a servo control system to rotate the swing arm 42 from interaction between a current applied to a VCM coil and a magnetic field generated by a magnet.
When power is applied to the hard disk drive, the disk 20 rotates, and the voice coil motor 45 rotates the swing arm 42 counterclockwise to move the head toward a position above a recording surface of the disk 20. When power is no longer applied to the hard disk drive, the disk 20 stops rotating, and the voice coil motor 45 rotates the swing arm 42 clockwise to move the head away from the disk 20.
Further referring to FIG. 1, a cover plate 12 is assembled to the base member 11 by using a plurality of screws 19. The cover plate 12 is desired to enclose and thus protect the disk 20 and the actuator 40 by keeping away dust and moisture from such disk drive components. Furthermore, the cover plate 12 is desired to minimize propagation of noise from operation of the disk drive.
In the disk drive of the prior art however, the cover plate 12 is typically manufactured into a flat shape by press-processing a thin stainless steel plate. The base member 11 is mainly manufactured of aluminum or an aluminum alloy by die-casting. With such a cover plate 12 of the prior art, the thickness of the cover plate 12 is much thinner than that of the base member 11. Thus, the cover plate 12 is not stiff enough, and as a result, a lot of vibrations and noise are generated from the disk drive during operation.
In addition, the size of the modern disk drive is desired to be further decreased to be more compact and slim. Thus, the distance between the components of the disk drive such as between the cover plate 12 and each of the disk 20, the spindle motor 30, and the actuator 40, decreases. The cover plate 12 which is not stiff enough deforms easily from external impact or load. Such a deformed cover plate 12 may contact the enclosed disk drive components resulting in interference with their operations or even damage of such components.
For example, disk drives used for portable computers such as notebook computers have limited height and weight. Thus, the thickness of the cover plate 12 is very thin, such as in a range of 0.4 mm to 0.5 mm for example. Such a thin cover plate 12 formed without sufficient stiffness is easily deformed.
Conventionally, to address such problems, a groove 13 and/or reinforcement ribs of various shapes are formed on the cover plate 12 to increase stiffness of the cover plate 12. However, such prior art techniques fail to result in sufficient stiffness for the cover plate 12.
Thus, a cover plate is desired to be formed with sufficient stiffness to protect disk drive components and to reduce noise of the disk drive, without being easily deformed.